Conventionally, it is known that a fuel vapor leak detecting device detects a fuel vapor leaked from a fuel tank. In JP-2005-69878A (US 2005/0044937), the fuel vapor leak detecting device switches a switching valve so that a tank passage is connected to one of an atmosphere passage and a pump passage and that the tank passage is disconnected from the other of the atmosphere passage and the pump passage. In a case where a vapor pressure of the fuel tank is lowered by driving a pump, if the vapor pressure does not become smaller than a threshold value, it is determined that an amount of a fuel vapor leak is larger than an allowed value.
In JP-2005-69878A, the switching valve has a valve shaft and a valve member opening or closing an end of a passage. The valve member is not integrated with the valve shaft, and is able to incline relative to the valve shaft within a specified angle range so as to reduce dispersions in perpendicularity and coaxiality between the valve member and the valve shaft.
However, in a case where the switching valve is closed, if the valve member is seated on a valve seat in the inclined state relative to the valve shaft, a sealing leak may occur between the valve member and the valve seat. Because a fuel vapor leak is detected based on a pressure detected when the valve member is closed, the fuel vapor leak may not be detected accurately due to the sealing leak.